STRATIGRAPHICAL GEOLOGY. 461 



Sandstone, with conglomerates and red clay; 2, the Vogesen 

 Sandstone ; 3, the Bunter Sandstone (gres bigarre). The 

 Vogesen Sandstone was regarded by Elie de Beaumont as an 

 equivalent of the Zechstein or Red Underlyer series, and he 

 thought the uprise of the Vogesen had taken place after its 

 deposition. The Bunter Sandstone was described as some- 

 times succeeding it unconformably, sometimes dissociated 

 from it by faults. On the other hand, the Bunter Sandstone 

 was said to pass gradually upward into Muschelkalk and the 

 latter into Keuper deposits (inarnes irrisees). 



In the year 1834 Alberti published his classic Monograph 

 of the Bunter Sandstone, Muschelkalk, and Keuper, and their 

 union as a formation. Alberti suggested that the name of 

 Trias be given to this formation, on the basis of the well- 

 marked character of the three sub-divisions. Starting from 

 his own observations in South-Western Germany, Alberti 

 drew a comparison between the deposits of the same 

 age in other parts of Europe. Each of these three main 

 divisions of the Trias was again sub-divided into a series of 

 groups or horizons of rock, which are all carefully established 

 upon stratigraphical, lithological, and palaeontological data. 



Alberti's sub-division of the Trias has remained the standard 

 of research in Germany, although one or two slight modifica- 

 tions have been made. In other countries the name was also 

 accepted, and the development of the Trias in Germany was 

 regarded as the leading type in Europe of the sedimentary suc- 

 cession which had accumulated during that period in the large 

 inland seas and lakes intermittently in open communication 

 with the sea. The Muschelkalk, which represented the longest 

 period of marine conditions in the German area, was found 

 however to be entirely absent in certain areas. 



William Smith had early pointed out the absence of the 

 Muschelkalk in Great Britain. Later researches by Conybeare 

 and Phillips, by Strickland (1833-37), by Murchison and 

 Buckland (1839), showed that in Great Britain the Bunter 

 beds are largely of estuarine origin, composed of sandstones, 

 pebble-beds, and conglomerates, while the Keuper beds are 

 also in places conglomeratic, or are red and white sandstones, 

 and pass upward into the characteristic red and green marls 

 containing local beds of gypsum and thick layers of rock-salt. 



A summary of the Triassic Succession was given by Quen- 

 stedt in his Flotz Series of Wurtemberg (1843). Quenstedt 



